Bending device

ABSTRACT

The bending device is adapted to bending of a longitudinal workpiece. The device comprises a bending die that has an outer shape corresponding to the bending shape, a clamping die that clamps the workpiece with the bending die, and a rotation mechanism that rotates the bending die and the clamping die to a predetermined bending direction while the workpiece is being clamped between the bending die and the clamping die. The rotation mechanism is provided with a selection mechanism that allows switching between a first rotation mode in which the bending die and the clamping die are rotated in a body and a second rotation mode in which one of the bending die and the clamping die is rotated independently of the other die.

FIELD OF THE INVENTION

This invention relates to a bending device, which bends a longitudinalworkpiece to both left and right sides.

BACKGROUND OF THE INVENTION

As disclosed in the Unexamined Japanese Patent Publication No.62-267024, a conventionally known bending device, which bends alongitudinal workpiece to both left and right sides, is provided with aright bending jig, including a pressure die, a bending die, and aclamping die, to be used in bending the workpiece to a right side, and aleft bending jig, including a pressure die, a bending die, and aclamping die, to be used in bending the workpiece to a left side.

When bending the workpiece to the right side, the right bending jig ismoved to the position corresponding to the center of right bending ofthe workpiece so as to execute right bending. When bending the workpieceto the left side, the left bending jig is moved to the positioncorresponding to the center of left bending of the workpiece so as toexecute left bending. Thus, bending to both the left and right sides isachieved.

SUMMARY OF THE INVENTION

However, in a conventional bending device as above, the right and leftbending jigs are moved to the positions corresponding to the respectivecenters for bending depending on the bending direction. Therefore, largeand heavy left and right jigs provided with the respective bending andclamping dies have to be moved in its entirety, thus making the devicecomplex and huge.

One object of the present invention is to provide a bending device whichis simple in structure and capable of bending a longitudinal workpieceto both the left and right sides.

To attain this and other objects, a bending device of the presentinvention comprises: a bending die that has an outer shape correspondingto a bending shape, a clamping die that clamps a workpiece with thebending die, and a rotation mechanism that rotates the bending die andthe clamping die to a predetermined bending direction while theworkpiece is being clamped between the bending die and the clamping die,so as to bend the workpiece.

The rotation mechanism includes a selection mechanism that allowsswitching between a first rotation mode in which the bending die and theclamping die are rotated in a body and a second rotation mode in whichone of the bending die and the clamping die is rotated independently ofthe other die.

According to the present invention, at least one of the bending die andthe clamping die is rotated by means of the selection mechanism.Therefore, it is possible to shift the respective positions of thebending die and the clamping die either to the positions for bending theworkpiece to a right side or to the positions for bending the workpieceto a left side.

Consequently, the present invention enables bending of the workpiece toboth the left and right sides, using a single pair of the bending dieand the clamping die. Thus, the configuration of the device can besimple.

In the present invention, the rotation mechanism may set the relativeposition between the bending die and the clamping die either to a firstrelative position which is an initial position when bending theworkpiece to the right side and to a second relative position which isan initial position when bending the workpiece to the left side, byrotating at least one of the bending die and the clamping die by meansof the selection mechanism.

In this manner, by feeding the workpiece between the bending die and theclamping die that are either in the first relative position or in thesecond relative position, bending of the workpiece to the right side orto the left side can be desirably executed.

The rotation mechanism may comprise a rotational force applicator thattransmits a rotational force to at least one of the bending die and theclamping die.

In the above case, the selection mechanism may transmit the rotationalforce from the rotational force applicator to both the bending die andthe clamping die in the first rotation mode, while the selectionmechanism may transmit the rotational force from the rotational forceapplicator to either of the bending die and the clamping die in thesecond rotation mode.

The bending die may have a linear section in its outer shape. In such acase, it is preferable that the clamping die may be designed to clampthe workpiece with the linear section of the bending die.

Then, compared with the case in which the workpiece is clamped between acurved section of the bending die and the clamping die, for example, itis difficult for positional deviation of the workpiece to occur betweenthe bending die and the clamping die upon bending.

The bending die may be provided with a first linear section in part ofits outer shape facing the clamping die when the relative positionbetween the bending die and the clamping die is in the first relativeposition, and with a second linear section in part of its outer shapefacing the clamping die when the relative position between the bendingdie and the clamping die is in the second relative position.

In this case, the clamping die clamps the workpiece with the firstlinear section of the bending die when the workpiece is being bent tothe right side, while the clamping die clamps the workpiece with thesecond linear section of the bending die when the workpiece is beingbent to the left side.

In the above case as well, occurrence of positional deviation of theworkpiece between the bending die and the clamping die upon bending isrelatively made difficult.

In the present invention, the clamping die may be a single die, or maybe composed of plural number of clamping dies.

For example, the clamping die may include a clamping die for right bendthat clamps the workpiece with the bending die when bending theworkpiece to the right side, and a clamping die for left bend thatclamps the workpiece with the bending die when bending the workpiece tothe left side.

Furthermore, in case that the relative position between the bending dieand the clamping die can be in the first relative position and thesecond relative position, the clamping dies for right bend and left bendmay be designed as follows.

That is, the clamping die for right bend may clamp the workpiece withthe first linear section of the bending die when bending the workpieceto the right side. Also, the clamping die for left bend may clamp theworkpiece with the second linear section of the bending die when bendingthe workpiece to the left side.

In this manner, even in the case of clamping the workpiece with eitherone of the clamping die for right bend and the clamping die for leftbend, occurrence of positional deviation of the workpiece being bentbetween the bending die and the clamping die (clamping die for rightbend or left bend) is relatively made difficult.

When the clamping dies for right bend and left bend are provided, it ispreferable that the clamping dies for right bend and left bend arearranged in such a manner that the moving directions of the respectiveclamping dies when clamping the workpiece are nearly parallel to eachother.

It is noted that the clamping dies for right bend and left bend may alsobe arranged in such a manner that the moving directions of therespective clamping dies when clamping the workpiece are not nearlyparallel.

In the present invention, the bending die may include in its outer shapea plurality of bending die contact portions which correspond to aplurality of bending shapes of the workpiece, and the clamping die mayinclude in its outer shape a plurality of clamping die contact portionswhich correspond to a plurality of bending shapes of the workpiece.

In the above case, the bending device may be constituted such that, whenthe workpiece is clamped between the bending die and the clamping die tobe bent, the workpiece is clamped between one of the bending die contactportions and one of the clamping die contact portions respectivelyselected in accordance with the bending shape of the workpiece.

In this manner, plural patterns of bending can be applied to theworkpiece.

When the clamping dies for right bend and left bend are provided, thefollowing constitution may be adopted.

That is, while the bending die has in its outer shape a plurality ofbending die contact portions which correspond to a plurality of bendingshapes of the workpiece, the clamping die for right bend may have in itsouter shape a plurality of clamping die contact portions for right bendwhich correspond to a plurality of bending shapes of the workpiece, andthe clamping die for left bend may have in its outer shape a pluralityof clamping die contact portions for left bend which correspond to aplurality of bending shapes of the workpiece.

In the above case, it is preferable that the bending device isconstituted such that, when the workpiece is clamped between the bendingdie and the clamping die for right bend to be bent to the right side,the workpiece is clamped between one of the bending die contact portionsand one of the clamping die contact portions for right bend respectivelyselected in accordance with the bending shape of the workpiece.

Also, it is preferable that the bending device is constituted such that,when the workpiece its clamped between the bending die and the clampingdie for left bend to be bent to the left side, the workpiece is clampedbetween one of the bending die contact portions and one of the clampingdie contact portions for left bend respectively selected in accordancewith the bending shape of the workpiece.

In such a manner as well, plural patterns of bending can be applied tothe workpiece.

Furthermore, in case that the clamping dies for right bend and left bendare provided, the bending device may be constituted as follows.

That is, when bending the workpiece to the right side, the clamping diefor right bend is moved toward the bending die so that the workpiece isclamped between the bending die and the clamping die for right bend.When bending the workpiece to the left side, the clamping die for leftbend is moved toward the bending die so that the workpiece is clampedbetween the bending die and the clamping die for left bend.

Conversely, when bending the workpiece to the right side, the bendingdie may be moved toward the clamping die for right bend so that theworkpiece is clamped between the bending die and the clamping die forright bend. When bending the workpiece to the left side, the bending diemay be moved toward the clamping die for left bend so that the workpieceis clamped between the bending die and the clamping die for left bend.

In order to perform appropriate bending of the workpiece to both theleft and right sides, the bending device of the present invention may beconstituted as below.

The bending device of the present invention may comprise a rightpressure die that receives a bending reaction force generated whenbending the workpiece to the right side, and a left pressure die thatreceives a bending reaction force generated when bending the workpieceto the left side.

In this case, the right pressure die and the left pressure die may bedisposed on both sides of the bending die.

When the bending die includes a plurality of bending die contactportions and the clamping die includes a plurality of clamping diecontact portions, the right and left pressure dies may be designed asbelow.

The right pressure die may include a plurality of right pressure diecontact portions corresponding to the shape of the workpiece, and theleft pressure die may include a plurality of left pressure die contactportions corresponding to the shape of the workpiece.

In the above case, when the workpiece is clamped between one of thebending die contact portions and one of the clamping die contactportions respectively selected in accordance with the bending shape ofthe workpiece to the right side, it is preferable that one of theplurality of right pressure die contact portions is in contact with theworkpiece to receive the bending reaction force. Similarly, when theworkpiece is clamped between one of the bending die contact portions andone of the clamping die contact portions respectively selected inaccordance with the bending shape of the workpiece to the left side, itis preferable that one of the plurality of left pressure die contactportions is in contact with the workpiece to receive the bendingreaction force.

The bending device of the present invention may comprise a chuck thatgrips the workpiece, and a feed mechanism that moves the chuck in alongitudinal direction of the workpiece and two directions which aredirections orthogonal to the longitudinal direction so as to feed theworkpiece between the bending die and the clamping die to be clampedtherebetween.

In the above manner, proper feeding of the workpiece is possible to theposition necessary for bending with the bending die and the clampingdie.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The invention will now be described, by way of example, with referenceto the accompanying drawings, in which:

FIG. 1 is an plan view showing a schematic constitution of a bendingdevice according to an embodiment of the present invention, in which astate is illustrated when bending a pipe as a workpiece to the rightside;

FIG. 2 is a partially enlarged cross sectional view, taken along theline II-II in FIG. 1;

FIG. 3 is a plan view showing a schematic constitution of the bendingdevice of the present embodiment, in which a state is illustrated whenbending the pipe to the left side;

FIG. 4 is a partially enlarged cross sectional view, taken along theline IV-IV in FIG. 3;

FIG. 5 is a partial side view of the bending device of the embodiment,viewed from the V direction in FIG. 2;

FIG. 6 is a partially enlarged cross sectional view, taken along theline VI-VI in FIG. 1;

FIG. 7 is a block diagram showing an electric constitution of thebending device of the embodiment;

FIG. 8 is a flowchart showing an example of a control process executedin an electronic control circuit of the bending device of theembodiment;

FIGS. 9A and 9B are explanatory views which illustrate a process whenbending the pipe to the right side; and

FIGS. 10A and 10B are explanatory views which illustrate a process whenbending the pipe to the left side.

BEST MODE TO CARRY OUT THE INVENTION

As shown in FIGS. 1 to 4, a bending device 100 of the present embodimentcomprises a bending die 6, a clamping die 50, a right pressure die 56, aleft pressure die 58, and a chuck 80. The clamping die 50 includes aclamping die 52 for right bend and a clamping die 54 for left bend.

As later explained, the bending device 100 bends a workpiece 1, such asa longitudinal pipe, to the right side (i.e., a direction of arrow R inFIG. 9A), by cooperation between the bending die 6, the clamping die 52for right bend, and the right pressure die 56. Also, the bending device100 bends the workpiece 1 to the left side (i.e., a direction of arrow Lin FIG. 10A), by cooperation between the bending die 6, the claming die54 for left bend, and the left pressure die 58.

The bending die 6 is provided in its outer shape with a plurality ofbending grooves 2 a, 2 b (see FIGS. 2 and 4) in tiers, as a plurality ofbending die contact portions corresponding to a plurality of bendingshapes of the workpiece 1. The bending grooves 2 a, 2 b are respectivelyformed into a shape corresponding to the outer shape of the workpiece 1.In the present embodiment, the bonding die 6 is provided with a largediameter portion 4 a having the bending groove 2 a in its outer shape,and a small diameter portion 4 b having the bending groove 2 b in itsouter shape. The large diameter portion 4 a and the small diameterportion 4 b are arranged in a stack in a vertical direction (i.e., adirection of arrow Z in FIGS. 2 and 4) orthogonal to the longitudinaldirection (i.e., a direction of arrow X in FIGS. 1 and 3) of theworkpiece 1.

The bending groove 2 a of the large diameter portion 4 a is formed intoa continuous groove including a semi-arc bending section 4 a 1, a firstlinear section 4 a 2, and a second linear section 4 a 3. The bendinggroove 2 b of the small diameter portion 4 b is formed into a continuousgroove including a semi-arc bending section 4 b 1, a first linearsection 4 b 2, and a second linear section 4 b 3. The large diameterportion 4 a and the small diameter portion 4 b are formed to besymmetrical in a lateral direction (i.e., a direction of arrow Y inFIGS. 1 and 3) of the workpiece 1.

A bending shaft 8 extends in the vertical direction (Z direction)orthogonal to the longitudinal direction of the workpiece 1 and isrotatably supported by a device body 10. The bending die 6 is fixed onan end face of the bending shaft 8. The bending shaft 8 functions as arotation axis of the bending die 6.

As shown in FIGS. 2 and 4, a bending arm 12 is rotatably supported onthe bending shaft 8. A pair of left and right clamping tables 14, 16 areswingably attached to the bending arm 12 via link mechanisms 18, 26. Onthe right clamping table 14, the clamping die 52 for right bend isprovided to face the bending die 6. Also, on the left clamping table 16,the clamping die 54 for left bend is provided to face the bending die 6.

As shown in FIG. 2, the link mechanism 18 includes a drive link 19 and adriven link 24. The link mechanism 18 supports the right clamping table14 so as to enable the right clamping table 14 to move close to or awayfrom the bending die 6. The drive link 19 and the driven link 24together form a parallel linkage.

Particularly, the drive link 19 includes a V-shaped link bar 20 and ahydraulic mechanism 21. One end 20 a of the V-shaped link bar 20 isrotatably supported on the right clamping table 14, and the other end 20b of the V-shaped link bar 20 is rotatably supported on a tip portion 22a of a rod 22 of the hydraulic mechanism 21. The hydraulic mechanism 21is provided with the rod 22 and a hydraulic cylinder 23. The hydrauliccylinder 23 is supported to the bending arm 12 so as to freely rotate ona rotation axis 23 a. The driven link 24 includes a linear link bar 25.One end 25 a of the link bar 25 is rotatably supported on the rightclamping table 14, and the other end 25 b is rotatably supported to thebending arm 12.

In the link mechanism 18, the rod 22 is pulled into the hydrauliccylinder 23 by the control of oil pressure applied to the hydrauliccylinder 23, so as to move the clamping die 52 for right bend close tothe bending die 6. Also, the rod 22 is pulled out of the hydrauliccylinder 23 so as to move the clamping die 52 for right bend away fromthe bending die 6.

On the other hand, as shown in FIG. 4, the link mechanism 26 supportingthe left clamping table 16 includes a drive link 27 having the functionand structure corresponding to the drive link 19, and a driven link 28having the function and structure corresponding to the driven link 24.

In the link mechanism 26, a rod 27 b is pulled into a hydraulic cylinder27 a by the control of oil pressure applied to the hydraulic cylinder 27a which is a component of the drive link 27, so as to move the clampingdie 54 for left bend close to the bending die 6. Also, the rod 27 b ispulled out of the hydraulic cylinder 27 a so as to move the clamping die54 for left bend away from the bending die 6.

As shown in FIG. 2, the clamping die 52 for right bend possesses, in itsouter shape portion facing the bending die 6, a plurality of bendinggrooves 52 a, 52 b in tiers as a plurality of clamping die contactportions for right bend corresponding to a plurality of bending shapesof the workpiece 1. The bending grooves 52 a, 52 b are linear grooveshaving the shape corresponding to the outer shape of the workpiece 1.The bending groove 52 a faces the bending groove 2 a of the bending die6, and the bending groove 52 b faces the bending groove 2 b of thebending die 6.

As shown in FIG. 4, the clamping die 54 for left bend possesses, in itsouter shape portion facing the bending die 6, a plurality of bendinggrooves 54 a, 54 b as a plurality of clamping die contact portions forleft bend corresponding to a plurality of bending shapes of theworkpiece 1. The bending grooves 54 a, 54 b are linear grooves havingthe shape corresponding to the outer shape of the workpiece 1. Thebending groove 54 a faces the bending groove 2 a of the bending die 6,and the bending groove 54 b faces the bending groove 2 b of the bendingdie 6.

When the relative position between the bending die 6 and the clampingdie 50 is in a first relative position which is an initial position whenbending the workpiece 1 to the right side (see FIG. 1), the bendinggrooves 52 a, 52 b of the clamping die 52 for right bend respectivelyface the first linear sections 4 a 2, 4 b 2 in the bending grooves 2 a,2 b of the bending die 6.

In this case, the rod 22 is pulled into the hydraulic cylinder 23, sothat the workpiece 1 can be clamped between the bending die 6 and theclamping die 52 for right bend (see FIG. 1). Particularly, the workpiece1 arranged in the first linear section 4 a 2 of the bending die 6 isclamped between the first linear section 4 a 2 of the bending die 6 andthe bending groove 52 a of the clamping die 52 for right bend (see FIG.2). Or, the workpiece 1 arranged in the first linear section 4 b 2 ofthe bending die 6 is clamped between the first linear section 4 b 2 ofthe bending die 6 and the bending groove 52 b of the clamping die 52 forright bend.

When the relative position between the bending die 6 and the clampingdie 50 is in a second relative position which is an initial positionwhen bending the workpiece 1 to the left side (see FIG. 3), the bendinggrooves 54 a, 54 b of the clamping die 54 for left bend respectivelyface the second linear sections 4 a 3, 4 b 3 in the bending grooves 2 a,2 b of the bending die 6.

In this case, the rod 27 b is pulled into the hydraulic cylinder 27 a,so that the workpiece 1 can be clamped between the bending die 6 and theclamping die 54 for left bend (see FIG. 3). Particularly, the workpiece1 arranged in the second linear section 4 a 3 of the bending die 6 isclamped between the second linear section 4 a 3 of the bending die 6 andthe bending groove 54 a of the clamping die 54 for left bend (see FIG.4). Or, the workpiece 1 arranged in the second linear section 4 b 3 ofthe bending die 6 is clamped between the second linear section 4 b 3 ofthe bending die 6 and the bending groove 54 b of the clamping die 54 forleft bend.

In the present embodiment, the clamping die 52 for right bend and theclamping die 54 for left bend are arranged in such a manner that theirmoving directions when clamping the workpiece 1 is nearly parallel toeach other.

As shown in FIGS. 2, 4 and 5, the bending shaft 8 is provided with aselection mechanism 30. The selection mechanism 30 allows switchingbetween a first rotation mode in which the bending die 6 and the bendingarm 12 (clamping die 50) are rotated in a body around the bending shaft8 and a second rotation mode in which only the bending die 6 out of thebending die 6 and the bending arm 12 (clamping die 50) is rotated aroundthe bending shaft 8.

The selection mechanism 30 includes a connection member 31, a clutchmember 33, a drive shaft 36, a motor 38, a belt 40, and a solenoid 46.

The connection member 31 is attached to a lower section of the bendingshaft 8. The connection member 31 is provided with a recess 32 formed onits bottom. The clutch member 33 is provided to face the connectionmember 31. The clutch member 33 possesses a projection 34 that isinserted into the recess 32. The clutch member 33 is slidably supportedon the drive shaft 36 disposed coaxially to the bending shaft 8. Theclutch member 33 can be slid in axial and circumferential directions ofthe drive shaft 36.

The upper end of the drive shaft 36 is inserted and fixed to theconnection member 31. The bending shaft 8 and the drive shaft 36 areconnected so as to rotate in a body. The drive shaft 36 is rotatablysupported to the device body 10. The drive shaft 36 is rotationallydriven via the belt 40 by the motor 38 as a rotational force applicatorattached to the device body 10.

A circular groove 42 is formed around the outer periphery of the clutchmember 33. A cam follower 45 attached to a tip end of a lever 44swingably supported to the device body 10 is fitted in the circulargroove 42. A rod 46 a of the solenoid 46 attached to the device body 10is connected to the other end of the lever 44. The clutch member 33 isslid in the axial direction of the drive shaft 36 by the drive of thesolenoid 46, so as to enable selection between connection and separationof the recess 32 and the projection 34.

As shown in FIGS. 2 and 4, the clutch member 33 has a portion 33 a thatprojects in a direction away from the drive shaft 36 along the bendingarm 12. A drive pin 48 provided upright on the bending arm 12 is engagedwith the portion 33 a.

Accordingly, when the clutch member 33 is rotated with the drive shaft36, rotation of the drive shaft 36 is transmitted to the bending arm 12via the clutch member 33 and the drive pin 48.

In other words, when the motor 38 is driven under the state that therecess 32 and the projection 34 are engaged, a rotational force of themotor 38 is transmitted to both the bending die 6 and the arm 12(clamping die 50) (i.e., first rotation mode). At this point, thebending die 6 and the clamping die 50 are rotated in a body around thebending shaft 8.

On the other hand, when the motor 38 is driven under the state that thesolenoid 46 is driven and the clutch member 33 is slid in the axialdirection (downward) of the drive shaft 36 via the cam follower 45 so asto separate the projection 34 from the recess 32, the rotational forceof the motor 38 is transmitted only to the bending die 6 out of thebending die 6 and the bending arm 12 (clamping die 50) (i.e., secondrotation mode). At this point, although the bending die 6 is rotatedaround the bending shaft 8, the clamping shaft 50 is in a halt state.

As shown in FIGS. 1, 3, and 6, the left and right pressure dies 66, 58are disposed on both left and right sides of the bending die 6 and theworkpiece 1.

The right pressure die 56 is attached to a right pressure table 60, andreceives a bending reaction force generated when bending the workpiece 1to the right side by the simultaneous rotation of the bending die 6 andthe clamping die 50 to the right side (see FIGS. 9A and 9B).

Particularly, the right pressure die 56 possesses, in its outer shapeportion facing the workpiece 1 when the workpiece 1 is clamped betweenthe bending die 6 and the clamping die 52 for right bend, a plurality ofbending grooves 66 a, 66 b in tiers as a plurality of right pressure diecontact portions corresponding to a plurality of bending shapes of theworkpiece 1. The bending grooves 56 a, 56 b are linear groovesrespectively having a shape corresponding to the outer shape of theworkpiece 1. The bending groove 56 a is pressed against the outerperiphery of the workpiece 1 when the workpiece 1 is clamped between thefirst linear portion 4 a 2 of the bending die 6 and the bending groove52 a of the clamping die 52 for right bend (see FIG. 6). Also, thebending groove 56 b is pressed against the outer periphery of theworkpiece 1 when the workpiece 1 is clamped between the first linearportion 4 b 2 of the bending die 6 and the bending groove 52 b of theclamping die 52 for right bend.

The left pressure die 58 is attached to a left pressure table 62, andreceives a bending reaction force generated when bending the workpiece 1to the left side by the simultaneous rotation of the bending die 6 andthe clamping die 50 to the left (see FIGS. 10A and 10B).

Particularly, the left pressure die 58 possesses, in its outer shapeportion facing the workpiece 1 when the workpiece 1 is clamped betweenthe bending die 6 and the clamping die 54 for left bend, a plurality ofbending grooves 58 a, 58 b in tiers as a plurality of left pressure diecontact portions corresponding to a plurality of bending shapes of theworkpiece 1. The bending grooves 58 a, 58 b are linear groovesrespectively having a shape corresponding to the outer shape of theworkpiece 1. The bending groove 68 a is pressed against the outerperiphery of the workpiece 1 when the workpiece 1 is clamped between thesecond linear portion 4 a 3 of the bending die 6 and the bending groove54 a of the clamping die 54 for left bend. Also, the bending groove 58 bis pressed against the outer periphery of the workpiece 1 when theworkpiece 1 is clamped between the second linear portion 4 b 3 of thebending die 6 and the bending groove 54 b of the clamping die 54 forleft bend.

The left and right pressure tables 60, 62 are movably supported to thedevice body 10 via respective link mechanisms 64, 72.

As shown in FIG. 6, the link mechanism 64 includes a drive link 65 and adriven link 70. The link mechanism 64 supports the right pressure table60 so as to enable the right pressure die 56 on the right pressure table60 to move close to or away from the workpiece 1. The drive link 65 andthe driven link 70 together form a parallel linkage.

Particularly, the drive link 65 includes a V-shaped link bar 66 and ahydraulic mechanism 67. One end 66 a of the V-shaped link bar 66 isrotatably supported on the right pressure table 60, and the other end 66b of the V-shaped link bar 66 is rotatably supported on a tip portion 68a of a rod 68 of the hydraulic mechanism 67. The hydraulic mechanism 67is provided with the rod 68 and a hydraulic cylinder 69. The hydrauliccylinder 69 is supported to a portion 11 a of the device body 10 so asto freely rotate on a rotation axis 69 a. The driven link 70 includes alinear link bar 71. One end 71 a of the link bar 71 is rotatablysupported on the right pressure table 60, and the other end 71 b isrotatably supported to the portion 11 a of the device body 10.

In the link mechanism 64, when bending the workpiece 1 to the rightside, the rod 68 is pulled into the hydraulic cylinder 69 by the controlof oil pressure applied to the hydraulic cylinder 69, so as to move theright pressure die 56 close to the workpiece 1. Also, the rod 68 ispulled out of the hydraulic cylinder 69 so as to move the right pressuredie 56 away from the workpiece 1.

On the other hand, as shown in FIG. 6, the link mechanism 72 supportingthe left pressure table 62 includes a drive link 73 having the functionand structure corresponding to the drive link 65, and a driven link 74having the function and structure corresponding to the driven link 70.

In the link mechanism 72, when bending the workpiece 1 to the left side,a rod 73 b is pulled into a hydraulic cylinder 73 a by the control ofoil pressure applied to the hydraulic cylinder 73 a which is a componentof the drive link 73, 80 as to move the left pressure die 58 close tothe workpiece 1. Also, the rod 73 b is pulled out of the hydrauliccylinder 73 a so as to move the left pressure die 58 away from theworkpiece 1.

As shown in FIGS. 1 and 3, a rear end of the workpiece 1 is gripped bythe chuck 80. The chuck 80 gripping the workpiece 1 is retained in afeed mechanism 82 provided in the device body 10 so that the chuck 80can be moved in three directions that is, the longitudinal direction ofthe workpiece 1 (a direction of arrow X in FIGS. 1 and 3), the lateraldirection orthogonal to the longitudinal direction (a direction of arrowY in FIGS. 1 and 3), and the vertical direction (a direction of arrow Zin FIGS. 2, 4 and 6).

The feed mechanism 82 includes rails 84, a feed table 86, and a movetable 90. The rails 84 are a pair of rails laid in the device body 10parallel to the longitudinal direction of the workpiece 1. The feedtable 86 can be moved in the longitudinal direction (X direction) alongthe rails 84 by the drive of a motor 116 a (see FIG. 7). A pair of rails88 extending in the lateral direction (Y direction) are provided on thefeed table 86. The move table 90 can be moved in the lateral direction(Y direction) along the rails 88 by the drive of a motor 116 b (see FIG.7). As shown in FIG. 6, a guide member 92 extending in the verticaldirection (Z direction) is provided upright on the move table 90. Thechuck 80 can be moved in the vertical direction (Z direction) along theguide member 92 by the drive of a motor 116 c (see FIG. 7).

Now, the electric system of the bending device of the present embodimentis described by way of a block diagram shown in FIG. 7. The presentdevice is driven and controlled by an electronic control circuit 101 toprocess the workpiece 1. The electronic circuit 101 mainly includes anarithmetic logic circuit including known CPU 102, ROM 104, RAM 106, andso on. The arithmetic logic circuit is connected to an external motorvia an input/output port 10880 as to input/output signal.

The CPU 102 inputs signal from respective position sensors 110 a, 110 b,110 c, 110 d, 110 e, 110 f, hog, and 110 h via the input/output port108.

Among the aforesaid position sensors, the position sensor 110 a includesan encoder that detects the rotation angle position of the drive axis 36(and consequently, the bending die 6 and the clamping die 50). Theposition sensor 110 b includes a limit switch that detects a forward endand a rearward end of the clamping die 62 for right bend that is movedclose to and away from the bending die 6 by the operation of the linkmechanism 18. The position sensor 110 c includes a limit switch thatdetects a forward end and a rearward end of the clamping die 54 for leftbend that is moved close to and away from the bending die 6 by theoperation of the link mechanism 26. The position sensor 110 d includes alimit switch that detects a forward end and a rearward end of the rightpressure die 56 that is moved close to and away from the workpiece 1 bythe operation of the link mechanism 64 at the time of bending theworkpiece 1 to the right side. The position sensor 110 e includes alimit switch that detects a forward end and a rearward end of the leftpressure die 58 that is moved close to and away from the workpiece 1 bythe operation of the link mechanism 72 at the time of bending theworkpiece 1 to the left side. The position sensor 110 f includes anencoder that detects rotation of the motor 116 a to detect the positionof the feed table 86 (chuck 80) in the longitudinal direction (Xdirection). The position sensor 110 g includes an encoder that detectsrotation of the motor 116 b to detect the position of the moving table90 (chuck 80) in the lateral direction (Y direction). The positionsensor 110 h includes an encoder that detects rotation of the motor 116c to detect the position of the chuck 80 in the vertical direction (Zdirection).

The CPU 102 outputs control signal based on data and signal from thesesensors and the data in the ROM 104 and RAM 106, via the input/outputport 108 and driving circuits 112 a, 112 b, 112 c, 112 d, 112 e, 112 f,112 g, 112 h, and 112 i, so as to control the respective drive systemsof the bending device.

In FIG. 7, a servo valve 114 a is a valve for controlling oil pressureapplied to the hydraulic cylinder 23, and a servo valve 114 b is a valvefor controlling oil pressure applied to the hydraulic cylinder 27 a. Aservo valve 114 c is a valve for controlling oil pressure applied to thehydraulic cylinder 69, and a servo valve 114 d is a valve forcontrolling oil pressure applied to the hydraulic cylinder 73 a.

Hereinafter, a process performed in the electronic control circuit 101based on the program data stored in the ROM 104, when the workpiece 1 isbent in the bending device of the present embodiment, is described byway of a flowchart illustrated in FIG. 8 and explanatory views shown inFIGS. 9A, 9B, 10A and 10B.

Firstly, the rear end of the workpiece 1 is gripped by the chuck 80(Step 200).

Then, the bending die 6 and the clamping die 50 are set at theiroriginal positions in accordance with the bending direction of bendingto be applied to the workpiece 1 (Step 210).

Particularly, when bending the workpiece 1 to the right side, therelative position between the bending die 6 and the clamping die 50 isset to the first relative position in which the bending grooves 52 a, 52b of the clamping die 52 for right bend face the first linear sections 4a 2, 4 b 2, respectively (see FIG. 1). At this point, the rod 22 ispulled out of the hydraulic cylinder 23 so that the clamping die 52 forright bend is spaced apart from the bending die 6.

When bending the workpiece 1 to the left side, the relative positionbetween the bending die 6 and the clamping die 50 is set to the secondrelative position in which the bending grooves 54 a, 54 b of theclamping die 54 for left bend face the second linear sections 4 a 3, 4 b3, respectively (see FIG. 3). At this point, the rod 27 b is pulled outof the hydraulic cylinder 27 a so that the clamping die 54 for left bendis spaced apart from the bending die 6.

In Step 210, the first rotation mode or the second rotation mode isachieved, where appropriate, depending on the control signal outputtedto the solenoid 46 via the drive circuit 112 b. By the control signaloutputted to the motor 38 via the drive circuit 112 a, at least one ofthe bending die 6 and the clamping die 50 is rotated around the bendingshaft 8, so as to achieve the aforementioned first relative position orsecond relative position. Achievement of the first relative position orsecond relative position is detected by the position sensor 110 a.

Next, by the control signal outputted to the motors 116 a, 116 b, and1.16 c via the drive circuits 112 g, 112 h, and 112 i, the chuck 80 ismoved so that the workpiece 1 is fed to the position between the bendingdie 6 and the clamping die 50 in accordance with the bending directionof the workpiece 1 (Step 220).

Particularly, when bending the workpiece 1 to the right side, theworkpiece 1 is arranged in the first linear section 4 a 2 or 4 b 2 ofthe bending die 6 in accordance with the bending shape of the workpiece1. When bending the workpiece 1 to the left, the workpiece 1 is arrangedin the second linear section 4 a 3 or 4 b 3 of the bending die 6 inaccordance with the bending shape of the workpiece 1.

In this state, the feed table 86 is moved toward the bending die 6 alongthe rails 84 by the drive of the motor 116 a.

The moving position of the feed table 86 (workpiece 1) in thelongitudinal direction (X direction) is detected by the position sensor110 f. The feed table 86 continues to be moved until the workpiece 1reaches the initial bending position with respect to the bending die 6and the clamping die 50 (Step 230: NO).

When it is detected that the workpiece 1 has reached the initial bendingposition based on signal from the position sensor 110 f (Step 230: YES),the move of the workpiece 1 by the feed mechanism 8 is stopped (Step240).

Next, drive signal is outputted to the servo valve 114 a via the drivecircuit 112 c or drive signal is outputted to the servo valve 114 b viathe drive circuit 112 d, so that the workpiece 1 is clamped between thebending die 6 and the claming die 50 (Step 250).

Particularly, when bending the workpiece 1 to the right side, the rod 22is pulled into the hydraulic cylinder 23, so that the workpiece 1 isclamped between the first linear section 4 a 2 of the bending die 6 andthe bending groove 52 a of the clamping die 52 for right bend, orbetween the first liner section 4 b 2 of the bending die 6 and thebending groove 52 b of the clamping die 52 for right bend.

When bending the workpiece 1 to the left side, the rod 27 b is pulledinto the hydraulic cylinder 27 a so that the workpiece 1 is clampedbetween the second linear section 4 a 3 of the bending die 6 and thebending groove 54 a of the clamping die 54 for left bend, or between thesecond liner section 4 b 3 of the bending die 6 and the bending groove54 b of the clamping die 54 for left bend.

In Step 250, after the workpiece 1 is clamped between the bending die 6and the clamping die 50 as above, the right pressure die 56 or the leftpressure die 58 is pressed against the workpiece 1.

Particularly, when bending the workpiece 1 to the right side, drivesignal is outputted to the servo valve 114 c via the drive circuit 112e. Consequently, the rod 68 is pulled into the hydraulic cylinder 69,and the bending groove 56 a or 56 b of the right pressure die 56 ispressed against the outer periphery of the workpiece 1 (see FIGS. 1, 6and 9A).

When bending the workpiece 1 to the left side, drive signal is outputtedto the servo valve 114 d via the drive circuit 112 f. Consequently, therod 73 b is pulled into the hydraulic cylinder 73 a, and the bendinggroove 58 a or 58 b of the left pressure die 58 is pressed against theouter periphery of the workpiece 1 (see FIGS. 3 and 10A).

Next, whether the bending to be executed to the workpiece 1 throughSteps 280 to 300 of the current flow (Steps 210 to 320 now in progress)is the final bending to the workpiece 1 is determined based on the datainputted from the outside to the CPU 102 (Step 260).

When it is positively determined in Step 260, that is, if there is nomore bending to be executed to the other part of the workpiece 1 (Step260: YES), the process moves to Step 270.

In Step 270, the gripping force to the workpiece 1 by the chuck 80 isloosened so as to release the workpiece 1 from the chuck 80 (Step 270).Then, the process moves to Step 280.

On the other hand, when it is negatively determined in Step 260, thatis, if there is another bending to be performed to the other part of theworkpiece 1 (Step 260: NO), the process moves to Step 280.

In Step 280, the bending die 6 and the clamping die 50 are rotated in abody around the bending shaft 8, by control signal outputted to themotor 38 via the drive circuit 112 a under the state that the firstrotation mode is achieved by the control signal outputted to thesolenoid 46 via the drive circuit 112 b.

As a result, the workpiece 1 is put around the bending groove 2 a or 2 bof the bending die 6 to be bent to the right or left side. The bendingreaction force at the time is received by the right pressure die 66 orthe left pressure die 58.

The bending angle (rotation angle of the bending die 6 and the clampingdie 60) at the time of bending is sequentially detected by the positionsensor 110 a. In the present embodiment, based on the detection value bythe position sensor 11 a, whether the bending angle has reached apredetermined angle is continuously determined during the bending (Step290). While it is negatively determined in Step 290 (Step 290: NO),bending by the bending die 6 and the clamping die 50 is continued. Whenit is positively determined (Step 290: YES), rotation of the bending die6 and the clamping die 50 is terminated to stop the bending (Step 300).

The aforementioned “predetermined angle” can be arbitrarily set to,e.g., approximately 180° and 90°. FIG. 9B shows the state in which thefirst bending has been completed (the state when Step 300 is completed),when the first bending direction of the workpiece 1 is right and theaforesaid “predetermined angle” is about 180°. In this case, theworkpiece 1 is bent to form a U-shape.

Next, the clamping of the workpiece 1 is released (Step 810).

Particularly, when the bending to the right side of the workpiece 1 iscomplete in Step 300, drive signal is outputted via the drive circuit112 c to the servo valve 114 a so as to pull the rod 22 out of thehydraulic cylinder 23. As a result, the clamping die 52 for right bendis separated from the bending die 6, the clamping of the workpiece 1 bythe bending die 6 and the clamping die 52 for right bend is released.Also, at this point, drive signal is outputted via the drive circuit 112e to the servo valve 114 c to pull the rod 68 out of the hydrauliccylinder 69. As a result, the right pressure die 56 is separated fromthe workpiece 1.

When the bending to the left side of the workpiece 1 is complete in Step300, drive signal is outputted via the drive circuit 112 d to the servovalve 114 b so as to pull the rod 27 b out of the hydraulic cylinder 27a. As a result, the clamping die 54 for left bend is separated from thebending die 6, the clamping of the workpiece 1 by the bending die 6 andthe clamping die 54 for left bend is released. Also, at this point,drive signal is outputted via the drive circuit 112 f to the servo valve114 d to pull the rod 73 b out of the hydraulic cylinder 73 a. As aresult, the left pressure die 58 is separated from the workpiece 1.

In the current flow, if Step 310 is completed without execution of Stop270, the workpiece 1 is still being gripped by the chuck 80 to beretained by the bending device 100.

On the other hand, if Step 310 is completed after the execution of Step270, the workpiece 1 is fully released from the bending device 100.

Next, whether the bending of the workpiece 1 just completed is the finalbending to the workpiece 1 is determined based on the data inputted fromthe outside to the CPU 102 (Step 320).

When it is negatively determined in Step 320, that is, if there isanother bending to be performed to the other part of the workpiece 1(Step 320: NO), the process moves to Step 210 and Steps 210 to 320 arerepeated.

In the above process, it is negatively determined in Step 320 only ifStep 270 is not executed in the current flow (if the workpiece 1 isstill being gripped by the chuck 80 in Step 320).

FIGS. 10A and 10B show the case in which bending of the workpiece 1 tothe left side is performed after the state shown in FIG. 9B.

In this case, firstly, the relative position between the bending die 6and the clamping die 60 is changed from the first relative position tothe second relative position (Step 210).

Particularly, by the control signal outputted via the drive circuit 112b to the solenoid 46, the second rotation mode (the state in which theprojection 34 is separated from the recess 32) is achieved. In thisstate, by the control signal outputted via the drive circuit 112 a tothe motor 38, the bending shaft 8 is rotated by 180° via the drive shaft36. As a result, the second relative position is achieved (see FIG.10A). This process is executed in a state that the workpiece 1 is movedaway from the moving paths of the bending die 6 and the clamping die 50,by the drive of the motors 116 a, 116 b, and 116 c, as needed, so thatthe workpiece 1 does not get in the way of the bending die 6 and theclamping die 50.

Also, the workpiece 1 is arranged in the second linear section 4 a 3 or4 b 3 of the bending die 6 in accordance with the bending shape of theworkpiece 1, by the drive of the motors 116 a, 116 b, and 116 c. By thedrive of the motor 116 a, the feed table 86 (workpiece 1) is moved andfed to the bending die 6 along the rails 84 (Step 220).

When the workpiece 1 has reached the bending position based on signalfrom the position sensor 110 f (Step 230: YES), the move of theworkpiece 1 by the feed mechanism 82 is stopped (Step 240).

In the above process, when Steps 210 to 320 are performed more than oncein order to perform bending to plural parts of the workpiece 1, Step 210for the second time onward is performed concurrently with Steps 220 to240.

Next, the rod 27 b is pulled into the hydraulic cylinder 27 a by theoutput of drive signal to the servo valve 114 b so as to produce a statein which the workpiece 1 is clamped between the bending die 6 and theclaming die 54 for left bend (Step 250). At this point, the bendinggroove 58 a or 58 b of the left pressure die 58 is pressed against theouter periphery of the workpiece 1 by the drive signal to the servovalve 114 d (see FIG. 10A).

Next, whether the bending to be executed to the workpiece 1 throughSteps 280 to 300 out of Steps 210 to 320 currently in progress is thefinal bending to the workpiece 1 is determined based on the datainputted from the outside to the CPU 102 (Step 260).

When it is positively determined in Step 260, the workpiece 1 isreleased from the chuck 80 (Step 270), and the process moves to Step280. On the other hand, when it is negatively determined in Step 260,the process moves to Step 280 without passing Step 270.

Next, while the first rotation mode (the state in which the projection34 is engaged with the recess 32) is achieved by the control signaloutputted via the drive circuit 112 b to the solenoid 46, the bendingdie 6 and the clamping die 50 are rotated in a body to the left side Lby the control signal outputted via the drive circuit 112 a to the motor38 (Step 280, FIG. 10B).

As a result, the workpiece 1 is bent to the left side. When it isdetermined that the bending angle of the workpiece 1 has reached thepredetermined angle based on the detection value by the position sensor110 a (Step 290: YES), the bending is stopped (Step 300). FIG. 10B showsthe state in which the process in Step 300 is completed when the“predetermined angle” at this point is around 180°. The clamping of theworkpiece 1 is released (Step 310).

Steps 210 to 320 are repeated predetermined times based on data inputtedfrom the outside to the CPU 102. When it is positively determined inStep 320 (Step 320: YES), the chuck 80 is returned to its originalposition by the control signal outputted via the drive circuits 112 g,112 h, and 112 i to the motors 116 a, 116 b, and 116 c (Step 330). Thepresent control process is terminated for the present.

As explained above, in the present embodiment, bending of the workpiece1 to both the left and right sides can be achieved by setting therelative position between the bending die 6 and the clamping die 60 tothe first relative position or the second relative position.

In other words, according to the present embodiment, the deviceconfiguration can be simple compared to the conventional deviceconfiguration since bending to both the left and right sides of theworkpiece 1 can be achieved by a pair of bending die 6 and the clampingdie 50.

Also, in the present embodiment, when the workpiece 1 is clamped betweenthe bending die 6 and the clamping die 50, the workpiece 1 is clampedbetween the linear section 4 a 2, 4 b 2, 4 a 3, 4 b 3 of the bendinggroove 2 a, 2 b of the bending die 6 and the linear bending groove 52 a,52 b, 54 a, 64 b of the clamping die 50.

Thus, according to the present embodiment, positional deviation hardlyoccurs between the bending die 6 and the clamping die 50 at the time ofbending the workpiece 1, compared to the case in which, for example,clamping of the workpiece 1 is performed using the curved section 4 a 1,4 b 1 of the bending groove 2 a, 2 b of the bending die 6.

In the present embodiment, the chuck 80 is designed to move in threedirections, that is, the longitudinal direction (X direction), thelateral direction (Y direction), and the vertical direction (Zdirection), by the feed mechanism 82. Accordingly, the presentembodiment makes it easy to feed the workpiece 1 to the positionnecessary for bending using the bending die 6 and the clamping die 50.

The present invention is not limited to the above embodiment, and othermodifications and variations are possible within the scope of thepresent invention.

For instance, in the above embodiment, both of the bending die 6 and thebending arm 12 (clamping die 50) are rotated through the transmission ofthe rotational force from the single motor 38.

However, two motors having the structure of the motor 38 may be providedas the drive force applicator. While the bending die 6 is rotated aroundthe bending shaft 8 by the rotational force of one motor, the bendingarm 12 (clamping die 50) may be rotated around the bending shaft 8 bythe rotational force of the other motor.

Also, for example, in the above embodiment, only the bending die 6 outof the bending die 6 and the bending arm 12 (clamping die 60) is rotatedaround the bending shaft 8 in the second rotation mode.

However, in the second rotation mode, only the bending arm 12 (clampingdie 50) out of the bending die 6 and the bending arm 12 (clamping die50) may be rotated around the bending shaft 8.

Such configuration can be easily implemented in the above variation inwhich the bending die 6 is rotated by one of the two motors having theconfiguration identical to the configuration of the motor 38 while thebending arm 12 (clamping die 50) is rotated by the other of the motors.

Particularly, the first rotation mode is achieved in which both thebending die 6 and the bending arm 12 (clamping die 50) are rotated bydriving both of the motors, while the second rotation mode is achievedin which only the bending arm 12 (clamping die 50) is rotated by drivingonly one of the motors that rotates the bending arm 12 (clamping die50).

1. A bending device that bends a longitudinal workpiece, comprising: abending die that has an outer shape corresponding to a bending shape; aclamping die that clamps the workpiece with the bending die; and arotation mechanism that rotates the bending die and the clamping die toa predetermined bending direction while the workpiece is being clampedbetween the bending die and the clamping die, wherein the rotationmechanism includes a selection mechanism that allows switching between afirst rotation mode in which the bending die and the clamping die arerotated in a body and a second rotation mode in which one of the bendingdie and the clamping die is rotated independently of the other die. 2.The bending device set forth in claim 1, wherein the rotation mechanismsets a relative position between the bonding die and the clamping dieeither to a first relative position, which is an initial position whenbending the workpiece to a right side, and to a second relativeposition, which is an initial position when bending the workpiece to aleft side, by rotating at least one of the bending die and the clampingdie by means of the selection mechanism.
 3. The bending device set forthin claim 1, wherein the rotation mechanism comprises a rotational forceapplicator that transmits a rotational force to at least one of thebending die and the clamping die, and the selection mechanism transmitsthe rotational force from the rotational force applicator to both thebending die and the clamping die in the first rotation mode, while theselection mechanism transmits the rotational force from the rotationalforce applicator to either of the bending die and the clamping die inthe second rotation mode.
 4. The bending device set forth in claim 3,wherein the selection mechanism transmits the rotational force from therotational force applicator only to the bending die out of the bendingdie and the clamping die in the second rotation mode.
 5. The bendingdevice set forth in claim 1, wherein the bending die has a linearsection in its outer shape, and the clamping die clamps the workpiecewith the linear section of the bending die.
 6. The bending device setforth in claim 2, wherein the bending die is provided with a firstlinear section in part of its outer shape facing the clamping die whenthe relative position between the bending die and the clamping die is inthe first relative position, and a second linear section in part of itsouter shape facing the clamping die when the relative position betweenthe bending die and the clamping die is in the second relative position,and the clamping die clamps the workpiece with the first linear sectionof the bending die when the workpiece is being bent to the right side,while the clamping die clamps the workpiece with the second linearsection of the bending die when the workpiece is being bent to the leftside.
 7. The bending device set forth in claim 1, wherein the clampingdie includes a clamping die for right bend that clamps the workpiecewith the bending die when bending the workpiece to a right side, and aclamping die for left bend that clamps the workpiece with the bendingdie when bending the workpiece to a left side.
 8. The bending device setforth in claim 6, wherein the clamping die includes a clamping die forright bend that clamps the workpiece with the first linear section ofthe bending die when bending the workpiece to the right side, and aclamping die for left bend that clamps the workpiece with the secondlinear section of the bending die when bending the workpiece to the leftside.
 9. The bending device set forth in claim 7, wherein the clampingdies for right bend and left bend are arranged in such a manner thatmoving directions of the respective clamping dies when clamping theworkpiece are nearly parallel to each other.
 10. The bending device setforth in claim 1, wherein the bending die includes in its outer shape aplurality of bending die contact portions which correspond to aplurality of bending shapes of the workpiece, the clamping die includesin its outer shape a plurality of clamping die contact portions whichcorrespond to a plurality of bending shapes of the workpiece, and whenthe workpiece is clamped between the bending die and the clamping die tobe bent, the workpiece is clamped between one of the bending die contactportions and one of the clamping die contact portions respectivelyselected in accordance with the bending shape of the workpiece.
 11. Thebending device set forth in claim 7, wherein the bending die has in itsouter shape a plurality of bending die contact portions which correspondto a plurality of bending shapes of the workpiece, the clamping die forright bend has in its outer shape a plurality of clamping die contactportions for right bend which correspond to a plurality of bendingshapes of the workpiece, and the clamping die for left bend has in itsouter shape a plurality of clamping die contact portions for left bendwhich correspond to a plurality of bending shapes of the workpiece, andwhen the workpiece is clamped between the bending die and the clampingdie for right bend to be bent to a right side, the workpiece is clampedbetween one of the bending die contact portions and one of the clampingdie contact portions for right bend respectively selected in accordancewith the bending shape of the workpiece, and when the workpiece isclamped between the bending die and the clamping die for left bend to bebent to a left side, the workpiece is clamped between one of the bendingdie contact portions and one of the clamping die contact portions forleft bend respectively selected in accordance with the bending shape ofthe workpiece.
 12. The bending device set forth in claim 7, wherein whenbending the workpiece to the right side, the clamping die for right bendis moved toward the bending die so that the workpiece is clamped betweenthe bending die and the clamping die for right bend, when bending theworkpiece to the left side, the clamping die for left bend is movedtoward the bending die so that the workpiece is clamped between thebending die and the clamping die for left bend.
 13. The bending deviceset forth in claim 1, further comprising a right pressure die thatreceives a bending reaction force generated when bending the workpieceto a right side, and a left pressure die that receives a bendingreaction force generated when bending the workpiece to a left side. 14.The bending device set forth in claim 13, wherein the right pressure dieand the left pressure die are disposed on both sides of the bending die.15. The bending device set forth in claim 10, further comprising a rightpressure die that receives a bending reaction force generated whenbending the workpiece to a right side, and a left pressure die thatreceives a bending reaction force generated when bending the workpieceto a left side, the right pressure die includes a plurality of rightpressure die contact portions corresponding to the shape of theworkpiece, and the left pressure die includes a plurality of leftpressure die contact portions corresponding to the shape of theworkpiece, and when the workpiece is clamped between one of the bendingdie contact portions and one of the clamping die contact portionsrespectively selected in accordance with the bending shape of theworkpiece to the right side, one of the plurality of right pressure diecontact portions is in contact with the workpiece to receive the bendingreaction force, and when the workpiece is clamped between one of thebending die contact portions and one of the clamping die contactportions respectively selected in accordance with the bending shape ofthe workpiece to the left side, one of the plurality of left pressuredie contact portions is in contact with the workpiece to receive thebending reaction force.
 16. The bending device set forth in claim 1,further comprising a chuck that grips the workpiece, and a feedmechanism that moves the chuck in a longitudinal direction of theworkpiece and two directions which are directions orthogonal to thelongitudinal direction so as to feed the workpiece between the bendingdie and the clamping die to be clamped therebetween.